Mucositis results in considerable morbidity and often undesired treatment interruption during definitive treatment for head and neck cancer with radiation +/- chemotherapy. A Phase I/II study of recombinant keratinocyte growth factor (KGF) is proposed in an attempt to overcome severe mucositis. Preliminary information including testing of recombinant keratinocyte growth factor in human volunteers and its interaction with therapeutic agents has been accomplished. Eligible patients with locally advanced head and neck cancer will receive definitive radiation + chemotherapy in a randomized, double-blind, placebo-controlled dose escalation study. Three dose levels are planned with the initiation of growth factor prior to radiation/chemotherapy and repeated weekly. Patients will be evaluated for acute effects up to 2 months after therapy and for lingering xerostomia, other late effects and quality of life for 1 year. Future studies would define the optimal dose and timing of KGF for head and neck cancer patients and adapt this agent for treatment of other sites (lung and esophagus) which are also affected by mucositis.